[PATCH v3 0/6] Improvements for MAX77620 GPIO driver

[PATCH v3 0/6] Improvements for MAX77620 GPIO driver

[Dmitry Osipenko]

Hello!

This series addresses a problem that I discovered on Nexus 7 device where
GPIO interrupts may be left enabled after bootloader and the driver isn't
prepared to this. It also makes a small improvements to the code, fixes the
non-released interrupt bug and converts driver to use irqchip template.

Changelog:

v3: - Addressed review comment that were made by Andy Shevchenko to v2:

        - Improved the commit message of the "Initialize hardware state of
          interrupts" patch.

        - Added these new patches:

           gpio: max77620: Don't set of_node
           gpio: max77620: Don't shadow error code of platform_get_irq()
           gpio: max77620: Use irqchip template

    - Added "Fix missing release of interrupt" patch.

v2: - Addressed review comment that were made by Andy Shevchenko to v1:

        - Generic init_hw() callback is used now for resetting interrupts.

        - These v1 patches are dropped:

           gpio: max77620: Replace interrupt-enable array with bitmap
           gpio: max77620: Don't handle disabled interrupts
           gpio: max77620: Move variable declaration

Dmitry Osipenko (6):
  gpio: max77620: Replace 8 with MAX77620_GPIO_NR
  gpio: max77620: Fix missing release of interrupt
  gpio: max77620: Don't set of_node
  gpio: max77620: Don't shadow error code of platform_get_irq()
  gpio: max77620: Use irqchip template
  gpio: max77620: Initialize hardware state of interrupts

 drivers/gpio/gpio-max77620.c | 65 ++++++++++++++++++++++++------------
 1 file changed, 44 insertions(+), 21 deletions(-)

-- 
2.26.0

[PATCH v3 0/6] Improvements for MAX77620 GPIO driver

[Dmitry Osipenko]

Hello!

This series addresses a problem that I discovered on Nexus 7 device where
GPIO interrupts may be left enabled after bootloader and the driver isn't
prepared to this. It also makes a small improvements to the code, fixes the
non-released interrupt bug and converts driver to use irqchip template.

Changelog:

v3: - Addressed review comment that were made by Andy Shevchenko to v2:

        - Improved the commit message of the "Initialize hardware state of
          interrupts" patch.

        - Added these new patches:

           gpio: max77620: Don't set of_node
           gpio: max77620: Don't shadow error code of platform_get_irq()
           gpio: max77620: Use irqchip template

    - Added "Fix missing release of interrupt" patch.

v2: - Addressed review comment that were made by Andy Shevchenko to v1:

        - Generic init_hw() callback is used now for resetting interrupts.

        - These v1 patches are dropped:

           gpio: max77620: Replace interrupt-enable array with bitmap
           gpio: max77620: Don't handle disabled interrupts
           gpio: max77620: Move variable declaration

Dmitry Osipenko (6):
  gpio: max77620: Replace 8 with MAX77620_GPIO_NR
  gpio: max77620: Fix missing release of interrupt
  gpio: max77620: Don't set of_node
  gpio: max77620: Don't shadow error code of platform_get_irq()
  gpio: max77620: Use irqchip template
  gpio: max77620: Initialize hardware state of interrupts

 drivers/gpio/gpio-max77620.c | 65 ++++++++++++++++++++++++------------
 1 file changed, 44 insertions(+), 21 deletions(-)

-- 
2.26.0

[PATCH v3 1/6] gpio: max77620: Replace 8 with MAX77620_GPIO_NR

[Dmitry Osipenko]

The MAX77620_GPIO_NR enum value represents the total number of GPIOs,
let's use it instead of a raw value in order to improve the code's
readability a tad.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/gpio/gpio-max77620.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpio/gpio-max77620.c b/drivers/gpio/gpio-max77620.c
index 313bd02dd893..4c0c9ec2587d 100644
--- a/drivers/gpio/gpio-max77620.c
+++ b/drivers/gpio/gpio-max77620.c
@@ -19,8 +19,8 @@ struct max77620_gpio {
 	struct regmap		*rmap;
 	struct device		*dev;
 	struct mutex		buslock; /* irq_bus_lock */
-	unsigned int		irq_type[8];
-	bool			irq_enabled[8];
+	unsigned int		irq_type[MAX77620_GPIO_NR];
+	bool			irq_enabled[MAX77620_GPIO_NR];
 };
 
 static irqreturn_t max77620_gpio_irqhandler(int irq, void *data)
@@ -38,7 +38,7 @@ static irqreturn_t max77620_gpio_irqhandler(int irq, void *data)
 
 	pending = value;
 
-	for_each_set_bit(offset, &pending, 8) {
+	for_each_set_bit(offset, &pending, MAX77620_GPIO_NR) {
 		unsigned int virq;
 
 		virq = irq_find_mapping(gpio->gpio_chip.irq.domain, offset);
-- 
2.26.0

[PATCH v3 2/6] gpio: max77620: Fix missing release of interrupt

[Dmitry Osipenko]

The requested interrupt is never released by the driver. Fix this by
using the resource-managed variant of request_threaded_irq().

Fixes: ab3dd9cc24d4 ("gpio: max77620: Fix interrupt handling")
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/gpio/gpio-max77620.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/gpio/gpio-max77620.c b/drivers/gpio/gpio-max77620.c
index 4c0c9ec2587d..7f7e8d4bf0d3 100644
--- a/drivers/gpio/gpio-max77620.c
+++ b/drivers/gpio/gpio-max77620.c
@@ -305,8 +305,9 @@ static int max77620_gpio_probe(struct platform_device *pdev)
 	gpiochip_irqchip_add_nested(&mgpio->gpio_chip, &max77620_gpio_irqchip,
 				    0, handle_edge_irq, IRQ_TYPE_NONE);
 
-	ret = request_threaded_irq(gpio_irq, NULL, max77620_gpio_irqhandler,
-				   IRQF_ONESHOT, "max77620-gpio", mgpio);
+	ret = devm_request_threaded_irq(&pdev->dev, gpio_irq, NULL,
+					max77620_gpio_irqhandler, IRQF_ONESHOT,
+					"max77620-gpio", mgpio);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "failed to request IRQ: %d\n", ret);
 		return ret;
-- 
2.26.0

[PATCH v3 3/6] gpio: max77620: Don't set of_node

[Dmitry Osipenko]

The gpiochip_add_data() takes care of setting the of_node to the parent's
device of_node, hence there is no need to do it manually in the driver's
code. This patch corrects the parent's device pointer and removes the
unnecessary setting of the of_node.

Suggested-by: Andy Shevchenko <andy.shevchenko-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Signed-off-by: Dmitry Osipenko <digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
 drivers/gpio/gpio-max77620.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/gpio/gpio-max77620.c b/drivers/gpio/gpio-max77620.c
index 7f7e8d4bf0d3..39d431da2dbc 100644
--- a/drivers/gpio/gpio-max77620.c
+++ b/drivers/gpio/gpio-max77620.c
@@ -279,7 +279,7 @@ static int max77620_gpio_probe(struct platform_device *pdev)
 	mgpio->dev = &pdev->dev;
 
 	mgpio->gpio_chip.label = pdev->name;
-	mgpio->gpio_chip.parent = &pdev->dev;
+	mgpio->gpio_chip.parent = pdev->dev.parent;
 	mgpio->gpio_chip.direction_input = max77620_gpio_dir_input;
 	mgpio->gpio_chip.get = max77620_gpio_get;
 	mgpio->gpio_chip.direction_output = max77620_gpio_dir_output;
@@ -288,9 +288,6 @@ static int max77620_gpio_probe(struct platform_device *pdev)
 	mgpio->gpio_chip.ngpio = MAX77620_GPIO_NR;
 	mgpio->gpio_chip.can_sleep = 1;
 	mgpio->gpio_chip.base = -1;
-#ifdef CONFIG_OF_GPIO
-	mgpio->gpio_chip.of_node = pdev->dev.parent->of_node;
-#endif
 
 	platform_set_drvdata(pdev, mgpio);
 
-- 
2.26.0

[PATCH v3 3/6] gpio: max77620: Don't set of_node

[Dmitry Osipenko]

The gpiochip_add_data() takes care of setting the of_node to the parent's
device of_node, hence there is no need to do it manually in the driver's
code. This patch corrects the parent's device pointer and removes the
unnecessary setting of the of_node.

Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/gpio/gpio-max77620.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/gpio/gpio-max77620.c b/drivers/gpio/gpio-max77620.c
index 7f7e8d4bf0d3..39d431da2dbc 100644
--- a/drivers/gpio/gpio-max77620.c
+++ b/drivers/gpio/gpio-max77620.c
@@ -279,7 +279,7 @@ static int max77620_gpio_probe(struct platform_device *pdev)
 	mgpio->dev = &pdev->dev;
 
 	mgpio->gpio_chip.label = pdev->name;
-	mgpio->gpio_chip.parent = &pdev->dev;
+	mgpio->gpio_chip.parent = pdev->dev.parent;
 	mgpio->gpio_chip.direction_input = max77620_gpio_dir_input;
 	mgpio->gpio_chip.get = max77620_gpio_get;
 	mgpio->gpio_chip.direction_output = max77620_gpio_dir_output;
@@ -288,9 +288,6 @@ static int max77620_gpio_probe(struct platform_device *pdev)
 	mgpio->gpio_chip.ngpio = MAX77620_GPIO_NR;
 	mgpio->gpio_chip.can_sleep = 1;
 	mgpio->gpio_chip.base = -1;
-#ifdef CONFIG_OF_GPIO
-	mgpio->gpio_chip.of_node = pdev->dev.parent->of_node;
-#endif
 
 	platform_set_drvdata(pdev, mgpio);
 
-- 
2.26.0

[PATCH v3 4/6] gpio: max77620: Don't shadow error code of platform_get_irq()

[Dmitry Osipenko]

The platform_get_irq() returns a positive interrupt number on success and
negative error code on failure (zero shouldn't ever happen in practice, it
would produce a noisy warning). Hence let's return the error code directly
instead of overriding it with -ENODEV.

Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/gpio/gpio-max77620.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/gpio/gpio-max77620.c b/drivers/gpio/gpio-max77620.c
index 39d431da2dbc..9121d2507f60 100644
--- a/drivers/gpio/gpio-max77620.c
+++ b/drivers/gpio/gpio-max77620.c
@@ -264,12 +264,14 @@ static int max77620_gpio_probe(struct platform_device *pdev)
 {
 	struct max77620_chip *chip =  dev_get_drvdata(pdev->dev.parent);
 	struct max77620_gpio *mgpio;
-	int gpio_irq;
+	unsigned int gpio_irq;
 	int ret;
 
-	gpio_irq = platform_get_irq(pdev, 0);
-	if (gpio_irq <= 0)
-		return -ENODEV;
+	ret = platform_get_irq(pdev, 0);
+	if (ret < 0)
+		return ret;
+
+	gpio_irq = ret;
 
 	mgpio = devm_kzalloc(&pdev->dev, sizeof(*mgpio), GFP_KERNEL);
 	if (!mgpio)
-- 
2.26.0

[PATCH v3 5/6] gpio: max77620: Use irqchip template

[Dmitry Osipenko]

This change addresses one of the GPIO-core TODOs for the MAX77620 driver
which requires modern drivers to use the irqchip template. Instead of
using the GPIO's irqchip-helpers for creating the IRQ domain, the
gpio_irq_chip structure is now filled by the driver itself and then
gpiochip_add_data() takes care of instantiating the IRQ domain for us.

Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/gpio/gpio-max77620.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/drivers/gpio/gpio-max77620.c b/drivers/gpio/gpio-max77620.c
index 9121d2507f60..6c516aa7732d 100644
--- a/drivers/gpio/gpio-max77620.c
+++ b/drivers/gpio/gpio-max77620.c
@@ -277,6 +277,7 @@ static int max77620_gpio_probe(struct platform_device *pdev)
 	if (!mgpio)
 		return -ENOMEM;
 
+	mutex_init(&mgpio->buslock);
 	mgpio->rmap = chip->rmap;
 	mgpio->dev = &pdev->dev;
 
@@ -291,6 +292,11 @@ static int max77620_gpio_probe(struct platform_device *pdev)
 	mgpio->gpio_chip.can_sleep = 1;
 	mgpio->gpio_chip.base = -1;
 
+	mgpio->gpio_chip.irq.chip = &max77620_gpio_irqchip;
+	mgpio->gpio_chip.irq.default_type = IRQ_TYPE_NONE;
+	mgpio->gpio_chip.irq.handler = handle_edge_irq;
+	mgpio->gpio_chip.irq.threaded = true;
+
 	platform_set_drvdata(pdev, mgpio);
 
 	ret = devm_gpiochip_add_data(&pdev->dev, &mgpio->gpio_chip, mgpio);
@@ -299,11 +305,6 @@ static int max77620_gpio_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	mutex_init(&mgpio->buslock);
-
-	gpiochip_irqchip_add_nested(&mgpio->gpio_chip, &max77620_gpio_irqchip,
-				    0, handle_edge_irq, IRQ_TYPE_NONE);
-
 	ret = devm_request_threaded_irq(&pdev->dev, gpio_irq, NULL,
 					max77620_gpio_irqhandler, IRQF_ONESHOT,
 					"max77620-gpio", mgpio);
@@ -312,9 +313,6 @@ static int max77620_gpio_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	gpiochip_set_nested_irqchip(&mgpio->gpio_chip, &max77620_gpio_irqchip,
-				    gpio_irq);
-
 	return 0;
 }
 
-- 
2.26.0

[PATCH v3 6/6] gpio: max77620: Initialize hardware state of interrupts

[Dmitry Osipenko]

I noticed on Nexus 7 that after rebooting from downstream kernel to
upstream, the GPIO interrupt is triggering non-stop despite interrupts
being disabled for all of GPIOs. This happens because Nexus 7 uses a
soft-reboot, meaning that bootloader should take care of resetting
hardware, but the bootloader doesn't do it well. As a result, GPIO
interrupt may be left ON at a boot time. Let's mask all GPIO interrupts
at the driver's initialization time in order to resolve the issue.

Signed-off-by: Dmitry Osipenko <digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
 drivers/gpio/gpio-max77620.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/drivers/gpio/gpio-max77620.c b/drivers/gpio/gpio-max77620.c
index 6c516aa7732d..e090979659eb 100644
--- a/drivers/gpio/gpio-max77620.c
+++ b/drivers/gpio/gpio-max77620.c
@@ -260,6 +260,30 @@ static int max77620_gpio_set_config(struct gpio_chip *gc, unsigned int offset,
 	return -ENOTSUPP;
 }
 
+static int max77620_gpio_irq_init_hw(struct gpio_chip *gc)
+{
+	struct max77620_gpio *gpio = gpiochip_get_data(gc);
+	unsigned int i;
+	int err;
+
+	/*
+	 * GPIO interrupts may be left ON after bootloader, hence let's
+	 * pre-initialize hardware to the expected state by disabling all
+	 * the interrupts.
+	 */
+	for (i = 0; i < MAX77620_GPIO_NR; i++) {
+		err = regmap_update_bits(gpio->rmap, GPIO_REG_ADDR(i),
+					 MAX77620_CNFG_GPIO_INT_MASK, 0);
+		if (err < 0) {
+			dev_err(gpio->dev,
+				"failed to disable interrupt: %d\n", err);
+			return err;
+		}
+	}
+
+	return 0;
+}
+
 static int max77620_gpio_probe(struct platform_device *pdev)
 {
 	struct max77620_chip *chip =  dev_get_drvdata(pdev->dev.parent);
@@ -295,6 +319,7 @@ static int max77620_gpio_probe(struct platform_device *pdev)
 	mgpio->gpio_chip.irq.chip = &max77620_gpio_irqchip;
 	mgpio->gpio_chip.irq.default_type = IRQ_TYPE_NONE;
 	mgpio->gpio_chip.irq.handler = handle_edge_irq;
+	mgpio->gpio_chip.irq.init_hw = max77620_gpio_irq_init_hw,
 	mgpio->gpio_chip.irq.threaded = true;
 
 	platform_set_drvdata(pdev, mgpio);
-- 
2.26.0

[PATCH v3 6/6] gpio: max77620: Initialize hardware state of interrupts

[Dmitry Osipenko]

I noticed on Nexus 7 that after rebooting from downstream kernel to
upstream, the GPIO interrupt is triggering non-stop despite interrupts
being disabled for all of GPIOs. This happens because Nexus 7 uses a
soft-reboot, meaning that bootloader should take care of resetting
hardware, but the bootloader doesn't do it well. As a result, GPIO
interrupt may be left ON at a boot time. Let's mask all GPIO interrupts
at the driver's initialization time in order to resolve the issue.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/gpio/gpio-max77620.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/drivers/gpio/gpio-max77620.c b/drivers/gpio/gpio-max77620.c
index 6c516aa7732d..e090979659eb 100644
--- a/drivers/gpio/gpio-max77620.c
+++ b/drivers/gpio/gpio-max77620.c
@@ -260,6 +260,30 @@ static int max77620_gpio_set_config(struct gpio_chip *gc, unsigned int offset,
 	return -ENOTSUPP;
 }
 
+static int max77620_gpio_irq_init_hw(struct gpio_chip *gc)
+{
+	struct max77620_gpio *gpio = gpiochip_get_data(gc);
+	unsigned int i;
+	int err;
+
+	/*
+	 * GPIO interrupts may be left ON after bootloader, hence let's
+	 * pre-initialize hardware to the expected state by disabling all
+	 * the interrupts.
+	 */
+	for (i = 0; i < MAX77620_GPIO_NR; i++) {
+		err = regmap_update_bits(gpio->rmap, GPIO_REG_ADDR(i),
+					 MAX77620_CNFG_GPIO_INT_MASK, 0);
+		if (err < 0) {
+			dev_err(gpio->dev,
+				"failed to disable interrupt: %d\n", err);
+			return err;
+		}
+	}
+
+	return 0;
+}
+
 static int max77620_gpio_probe(struct platform_device *pdev)
 {
 	struct max77620_chip *chip =  dev_get_drvdata(pdev->dev.parent);
@@ -295,6 +319,7 @@ static int max77620_gpio_probe(struct platform_device *pdev)
 	mgpio->gpio_chip.irq.chip = &max77620_gpio_irqchip;
 	mgpio->gpio_chip.irq.default_type = IRQ_TYPE_NONE;
 	mgpio->gpio_chip.irq.handler = handle_edge_irq;
+	mgpio->gpio_chip.irq.init_hw = max77620_gpio_irq_init_hw,
 	mgpio->gpio_chip.irq.threaded = true;
 
 	platform_set_drvdata(pdev, mgpio);
-- 
2.26.0

Re: [PATCH v3 3/6] gpio: max77620: Don't set of_node

[Dmitry Osipenko]

08.07.2020 23:57, Andy Shevchenko пишет:
> 
> 
> On Wednesday, July 8, 2020, Dmitry Osipenko <digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org
> <mailto:digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>> wrote:
> 
>     The gpiochip_add_data() takes care of setting the of_node to the
>     parent's
>     device of_node, hence there is no need to do it manually in the driver's
>     code. This patch corrects the parent's device pointer and removes the
>     unnecessary setting of the of_node.
> 
> 
> I gave a second look and I think my suggestion is wrong. Here is an
> interesting propagation of the parent device node to its grand son,
> leaving son’s one untouched. Original code has intentions to do that way.

The [1] says that gpio_chip.parent should point at the "device providing
the GPIOs". That's the pdev->dev.parent in the case of this driver.
MAX77620 is an MFD PMIC device that has virtual sub-devices like GPIO
controller, PINCTRL and RTC. The MFD is the parent device that provides
the GPIOs [2].

[1]
https://elixir.bootlin.com/linux/v5.8-rc3/source/include/linux/gpio/driver.h#L276

[2]
https://elixir.bootlin.com/linux/v5.8-rc3/source/arch/arm64/boot/dts/nvidia/tegra210-p2180.dtsi#L48

I think the old code was wrong and this patch is correct, please correct
me if I'm missing something.

>     Suggested-by: Andy Shevchenko <andy.shevchenko-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org
>     <mailto:andy.shevchenko-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>>
>     Signed-off-by: Dmitry Osipenko <digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org
>     <mailto:digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>>
>     ---
>      drivers/gpio/gpio-max77620.c | 5 +----
>      1 file changed, 1 insertion(+), 4 deletions(-)
> 
>     diff --git a/drivers/gpio/gpio-max77620.c b/drivers/gpio/gpio-max77620.c
>     index 7f7e8d4bf0d3..39d431da2dbc 100644
>     --- a/drivers/gpio/gpio-max77620.c
>     +++ b/drivers/gpio/gpio-max77620.c
>     @@ -279,7 +279,7 @@ static int max77620_gpio_probe(struct
>     platform_device *pdev)
>             mgpio->dev = &pdev->dev;
> 
>             mgpio->gpio_chip.label = pdev->name;
>     -       mgpio->gpio_chip.parent = &pdev->dev;
>     +       mgpio->gpio_chip.parent = pdev->dev.parent;
>             mgpio->gpio_chip.direction_input = max77620_gpio_dir_input;
>             mgpio->gpio_chip.get = max77620_gpio_get;
>             mgpio->gpio_chip.direction_output = max77620_gpio_dir_output;
>     @@ -288,9 +288,6 @@ static int max77620_gpio_probe(struct
>     platform_device *pdev)
>             mgpio->gpio_chip.ngpio = MAX77620_GPIO_NR;
>             mgpio->gpio_chip.can_sleep = 1;
>             mgpio->gpio_chip.base = -1;
>     -#ifdef CONFIG_OF_GPIO
>     -       mgpio->gpio_chip.of_node = pdev->dev.parent->of_node;
>     -#endif
> 
>             platform_set_drvdata(pdev, mgpio);
>      
>     -- 
>     2.26.0
> 
> 
> 
> -- 
> With Best Regards,
> Andy Shevchenko
> 
> 

Re: [PATCH v3 3/6] gpio: max77620: Don't set of_node

[Dmitry Osipenko]

08.07.2020 23:57, Andy Shevchenko пишет:
> 
> 
> On Wednesday, July 8, 2020, Dmitry Osipenko <digetx@gmail.com
> <mailto:digetx@gmail.com>> wrote:
> 
>     The gpiochip_add_data() takes care of setting the of_node to the
>     parent's
>     device of_node, hence there is no need to do it manually in the driver's
>     code. This patch corrects the parent's device pointer and removes the
>     unnecessary setting of the of_node.
> 
> 
> I gave a second look and I think my suggestion is wrong. Here is an
> interesting propagation of the parent device node to its grand son,
> leaving son’s one untouched. Original code has intentions to do that way.

The [1] says that gpio_chip.parent should point at the "device providing
the GPIOs". That's the pdev->dev.parent in the case of this driver.
MAX77620 is an MFD PMIC device that has virtual sub-devices like GPIO
controller, PINCTRL and RTC. The MFD is the parent device that provides
the GPIOs [2].

[1]
https://elixir.bootlin.com/linux/v5.8-rc3/source/include/linux/gpio/driver.h#L276

[2]
https://elixir.bootlin.com/linux/v5.8-rc3/source/arch/arm64/boot/dts/nvidia/tegra210-p2180.dtsi#L48

I think the old code was wrong and this patch is correct, please correct
me if I'm missing something.

>     Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com
>     <mailto:andy.shevchenko@gmail.com>>
>     Signed-off-by: Dmitry Osipenko <digetx@gmail.com
>     <mailto:digetx@gmail.com>>
>     ---
>      drivers/gpio/gpio-max77620.c | 5 +----
>      1 file changed, 1 insertion(+), 4 deletions(-)
> 
>     diff --git a/drivers/gpio/gpio-max77620.c b/drivers/gpio/gpio-max77620.c
>     index 7f7e8d4bf0d3..39d431da2dbc 100644
>     --- a/drivers/gpio/gpio-max77620.c
>     +++ b/drivers/gpio/gpio-max77620.c
>     @@ -279,7 +279,7 @@ static int max77620_gpio_probe(struct
>     platform_device *pdev)
>             mgpio->dev = &pdev->dev;
> 
>             mgpio->gpio_chip.label = pdev->name;
>     -       mgpio->gpio_chip.parent = &pdev->dev;
>     +       mgpio->gpio_chip.parent = pdev->dev.parent;
>             mgpio->gpio_chip.direction_input = max77620_gpio_dir_input;
>             mgpio->gpio_chip.get = max77620_gpio_get;
>             mgpio->gpio_chip.direction_output = max77620_gpio_dir_output;
>     @@ -288,9 +288,6 @@ static int max77620_gpio_probe(struct
>     platform_device *pdev)
>             mgpio->gpio_chip.ngpio = MAX77620_GPIO_NR;
>             mgpio->gpio_chip.can_sleep = 1;
>             mgpio->gpio_chip.base = -1;
>     -#ifdef CONFIG_OF_GPIO
>     -       mgpio->gpio_chip.of_node = pdev->dev.parent->of_node;
>     -#endif
> 
>             platform_set_drvdata(pdev, mgpio);
>      
>     -- 
>     2.26.0
> 
> 
> 
> -- 
> With Best Regards,
> Andy Shevchenko
> 
> 

Re: [PATCH v1 0/5] Improvements for MAX77620 GPIO driver

[Dmitry Osipenko]

09.07.2020 00:00, Andy Shevchenko пишет:
> 
> 
> On Wednesday, July 8, 2020, Dmitry Osipenko <digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org
> <mailto:digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>> wrote:
> 
>     Hello!
> 
>     This series addresses a problem that I discovered on Nexus 7 device
>     where
>     GPIO interrupts may be left enabled after bootloader and the driver
>     isn't
>     prepared to this. It also makes a small improvements to the code,
>     fixes the
>     non-released interrupt bug and converts driver to use irqchip template.
> 
> 
> Thanks! I commented on one patch, the rest looks good and you may add my
> Rb tag.

Thank you! :)

Re: [PATCH v1 0/5] Improvements for MAX77620 GPIO driver

[Dmitry Osipenko]

09.07.2020 00:00, Andy Shevchenko пишет:
> 
> 
> On Wednesday, July 8, 2020, Dmitry Osipenko <digetx@gmail.com
> <mailto:digetx@gmail.com>> wrote:
> 
>     Hello!
> 
>     This series addresses a problem that I discovered on Nexus 7 device
>     where
>     GPIO interrupts may be left enabled after bootloader and the driver
>     isn't
>     prepared to this. It also makes a small improvements to the code,
>     fixes the
>     non-released interrupt bug and converts driver to use irqchip template.
> 
> 
> Thanks! I commented on one patch, the rest looks good and you may add my
> Rb tag.

Thank you! :)

Re: [PATCH v3 3/6] gpio: max77620: Don't set of_node

[Andy Shevchenko]

On Thu, Jul 9, 2020 at 12:44 AM Dmitry Osipenko <digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> 08.07.2020 23:57, Andy Shevchenko пишет:
> > On Wednesday, July 8, 2020, Dmitry Osipenko <digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org
> > <mailto:digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>> wrote:

...

> > I gave a second look and I think my suggestion is wrong. Here is an
> > interesting propagation of the parent device node to its grand son,
> > leaving son’s one untouched. Original code has intentions to do that way.
>
> The [1] says that gpio_chip.parent should point at the "device providing
> the GPIOs".

Yes, physical device I believe.

> That's the pdev->dev.parent in the case of this driver.
> MAX77620 is an MFD PMIC device that has virtual sub-devices like GPIO
> controller, PINCTRL and RTC. The MFD is the parent device that provides
> the GPIOs [2].
>
> [1]
> https://elixir.bootlin.com/linux/v5.8-rc3/source/include/linux/gpio/driver.h#L276
>
> [2]
> https://elixir.bootlin.com/linux/v5.8-rc3/source/arch/arm64/boot/dts/nvidia/tegra210-p2180.dtsi#L48
>
> I think the old code was wrong and this patch is correct, please correct
> me if I'm missing something.

Hmm... I have checked through GPIO drivers I have knowledge of / care
about and PMIC ones do like you suggested in this patch, the rest
(which are instantiated from MFD) take a virtual platform device.

Looking at DT excerpt I think you're rather right than wrong, so I
leave it to you and maintainers.
Thanks!

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v3 3/6] gpio: max77620: Don't set of_node

[Andy Shevchenko]

On Thu, Jul 9, 2020 at 12:44 AM Dmitry Osipenko <digetx@gmail.com> wrote:
> 08.07.2020 23:57, Andy Shevchenko пишет:
> > On Wednesday, July 8, 2020, Dmitry Osipenko <digetx@gmail.com
> > <mailto:digetx@gmail.com>> wrote:

...

> > I gave a second look and I think my suggestion is wrong. Here is an
> > interesting propagation of the parent device node to its grand son,
> > leaving son’s one untouched. Original code has intentions to do that way.
>
> The [1] says that gpio_chip.parent should point at the "device providing
> the GPIOs".

Yes, physical device I believe.

> That's the pdev->dev.parent in the case of this driver.
> MAX77620 is an MFD PMIC device that has virtual sub-devices like GPIO
> controller, PINCTRL and RTC. The MFD is the parent device that provides
> the GPIOs [2].
>
> [1]
> https://elixir.bootlin.com/linux/v5.8-rc3/source/include/linux/gpio/driver.h#L276
>
> [2]
> https://elixir.bootlin.com/linux/v5.8-rc3/source/arch/arm64/boot/dts/nvidia/tegra210-p2180.dtsi#L48
>
> I think the old code was wrong and this patch is correct, please correct
> me if I'm missing something.

Hmm... I have checked through GPIO drivers I have knowledge of / care
about and PMIC ones do like you suggested in this patch, the rest
(which are instantiated from MFD) take a virtual platform device.

Looking at DT excerpt I think you're rather right than wrong, so I
leave it to you and maintainers.
Thanks!

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v3 3/6] gpio: max77620: Don't set of_node

[Dmitry Osipenko]

09.07.2020 12:07, Andy Shevchenko пишет:
> On Thu, Jul 9, 2020 at 12:44 AM Dmitry Osipenko <digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>> 08.07.2020 23:57, Andy Shevchenko пишет:
>>> On Wednesday, July 8, 2020, Dmitry Osipenko <digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org
>>> <mailto:digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>> wrote:
> 
> ...
> 
>>> I gave a second look and I think my suggestion is wrong. Here is an
>>> interesting propagation of the parent device node to its grand son,
>>> leaving son’s one untouched. Original code has intentions to do that way.
>>
>> The [1] says that gpio_chip.parent should point at the "device providing
>> the GPIOs".
> 
> Yes, physical device I believe.
> 
>> That's the pdev->dev.parent in the case of this driver.
>> MAX77620 is an MFD PMIC device that has virtual sub-devices like GPIO
>> controller, PINCTRL and RTC. The MFD is the parent device that provides
>> the GPIOs [2].
>>
>> [1]
>> https://elixir.bootlin.com/linux/v5.8-rc3/source/include/linux/gpio/driver.h#L276
>>
>> [2]
>> https://elixir.bootlin.com/linux/v5.8-rc3/source/arch/arm64/boot/dts/nvidia/tegra210-p2180.dtsi#L48
>>
>> I think the old code was wrong and this patch is correct, please correct
>> me if I'm missing something.
> 
> Hmm... I have checked through GPIO drivers I have knowledge of / care
> about and PMIC ones do like you suggested in this patch, the rest
> (which are instantiated from MFD) take a virtual platform device.
> 
> Looking at DT excerpt I think you're rather right than wrong, so I
> leave it to you and maintainers.
> Thanks!

Okay, waiting for the maintainers then :)

Thank you very much for the review!

Re: [PATCH v3 3/6] gpio: max77620: Don't set of_node

[Dmitry Osipenko]

09.07.2020 12:07, Andy Shevchenko пишет:
> On Thu, Jul 9, 2020 at 12:44 AM Dmitry Osipenko <digetx@gmail.com> wrote:
>> 08.07.2020 23:57, Andy Shevchenko пишет:
>>> On Wednesday, July 8, 2020, Dmitry Osipenko <digetx@gmail.com
>>> <mailto:digetx@gmail.com>> wrote:
> 
> ...
> 
>>> I gave a second look and I think my suggestion is wrong. Here is an
>>> interesting propagation of the parent device node to its grand son,
>>> leaving son’s one untouched. Original code has intentions to do that way.
>>
>> The [1] says that gpio_chip.parent should point at the "device providing
>> the GPIOs".
> 
> Yes, physical device I believe.
> 
>> That's the pdev->dev.parent in the case of this driver.
>> MAX77620 is an MFD PMIC device that has virtual sub-devices like GPIO
>> controller, PINCTRL and RTC. The MFD is the parent device that provides
>> the GPIOs [2].
>>
>> [1]
>> https://elixir.bootlin.com/linux/v5.8-rc3/source/include/linux/gpio/driver.h#L276
>>
>> [2]
>> https://elixir.bootlin.com/linux/v5.8-rc3/source/arch/arm64/boot/dts/nvidia/tegra210-p2180.dtsi#L48
>>
>> I think the old code was wrong and this patch is correct, please correct
>> me if I'm missing something.
> 
> Hmm... I have checked through GPIO drivers I have knowledge of / care
> about and PMIC ones do like you suggested in this patch, the rest
> (which are instantiated from MFD) take a virtual platform device.
> 
> Looking at DT excerpt I think you're rather right than wrong, so I
> leave it to you and maintainers.
> Thanks!

Okay, waiting for the maintainers then :)

Thank you very much for the review!

Re: [PATCH v3 1/6] gpio: max77620: Replace 8 with MAX77620_GPIO_NR

[Laxman Dewangan]

On Thursday 09 July 2020 01:53 AM, Dmitry Osipenko wrote:
> External email: Use caution opening links or attachments
>
>
> The MAX77620_GPIO_NR enum value represents the total number of GPIOs,
> let's use it instead of a raw value in order to improve the code's
> readability a tad.
>
> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
>

Looks good to me.
Acked-by: Laxman Dewangan <ldewangan@nvidia.com>

Re: [PATCH v3 1/6] gpio: max77620: Replace 8 with MAX77620_GPIO_NR

[Laxman Dewangan]

On Thursday 09 July 2020 01:53 AM, Dmitry Osipenko wrote:
> External email: Use caution opening links or attachments
>
>
> The MAX77620_GPIO_NR enum value represents the total number of GPIOs,
> let's use it instead of a raw value in order to improve the code's
> readability a tad.
>
> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
>

Looks good to me.
Acked-by: Laxman Dewangan <ldewangan@nvidia.com>

Re: [PATCH v3 2/6] gpio: max77620: Fix missing release of interrupt

[Laxman Dewangan]

On Thursday 09 July 2020 01:53 AM, Dmitry Osipenko wrote:
> External email: Use caution opening links or attachments
>
>
> The requested interrupt is never released by the driver. Fix this by
> using the resource-managed variant of request_threaded_irq().
>
> Fixes: ab3dd9cc24d4 ("gpio: max77620: Fix interrupt handling")
> Signed-off-by: Dmitry Osipenko <digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>


Looks good to me.
Acked-by: Laxman Dewangan <ldewangan-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>

Re: [PATCH v3 2/6] gpio: max77620: Fix missing release of interrupt

[Laxman Dewangan]

On Thursday 09 July 2020 01:53 AM, Dmitry Osipenko wrote:
> External email: Use caution opening links or attachments
>
>
> The requested interrupt is never released by the driver. Fix this by
> using the resource-managed variant of request_threaded_irq().
>
> Fixes: ab3dd9cc24d4 ("gpio: max77620: Fix interrupt handling")
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>


Looks good to me.
Acked-by: Laxman Dewangan <ldewangan@nvidia.com>

Re: [PATCH v3 3/6] gpio: max77620: Don't set of_node

[Laxman Dewangan]

On Thursday 09 July 2020 01:53 AM, Dmitry Osipenko wrote:
> External email: Use caution opening links or attachments
>
>
> The gpiochip_add_data() takes care of setting the of_node to the parent's
> device of_node, hence there is no need to do it manually in the driver's
> code. This patch corrects the parent's device pointer and removes the
> unnecessary setting of the of_node.
>
> Suggested-by: Andy Shevchenko <andy.shevchenko-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> Signed-off-by: Dmitry Osipenko <digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
>


Looks good to me.
Acked-by: Laxman Dewangan <ldewangan-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>

Re: [PATCH v3 3/6] gpio: max77620: Don't set of_node

[Laxman Dewangan]

On Thursday 09 July 2020 01:53 AM, Dmitry Osipenko wrote:
> External email: Use caution opening links or attachments
>
>
> The gpiochip_add_data() takes care of setting the of_node to the parent's
> device of_node, hence there is no need to do it manually in the driver's
> code. This patch corrects the parent's device pointer and removes the
> unnecessary setting of the of_node.
>
> Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
>


Looks good to me.
Acked-by: Laxman Dewangan <ldewangan@nvidia.com>

Re: [PATCH v3 4/6] gpio: max77620: Don't shadow error code of platform_get_irq()

[Laxman Dewangan]

On Thursday 09 July 2020 01:53 AM, Dmitry Osipenko wrote:
> External email: Use caution opening links or attachments
>
>
> The platform_get_irq() returns a positive interrupt number on success and
> negative error code on failure (zero shouldn't ever happen in practice, it
> would produce a noisy warning). Hence let's return the error code directly
> instead of overriding it with -ENODEV.
>
> Suggested-by: Andy Shevchenko <andy.shevchenko-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> Signed-off-by: Dmitry Osipenko <digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
>


Looks good to me.
Acked-by: Laxman Dewangan <ldewangan-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>

Re: [PATCH v3 4/6] gpio: max77620: Don't shadow error code of platform_get_irq()

[Laxman Dewangan]

On Thursday 09 July 2020 01:53 AM, Dmitry Osipenko wrote:
> External email: Use caution opening links or attachments
>
>
> The platform_get_irq() returns a positive interrupt number on success and
> negative error code on failure (zero shouldn't ever happen in practice, it
> would produce a noisy warning). Hence let's return the error code directly
> instead of overriding it with -ENODEV.
>
> Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
>


Looks good to me.
Acked-by: Laxman Dewangan <ldewangan@nvidia.com>

Re: [PATCH v3 5/6] gpio: max77620: Use irqchip template

[Laxman Dewangan]

On Thursday 09 July 2020 01:53 AM, Dmitry Osipenko wrote:
> External email: Use caution opening links or attachments
>
>
> This change addresses one of the GPIO-core TODOs for the MAX77620 driver
> which requires modern drivers to use the irqchip template. Instead of
> using the GPIO's irqchip-helpers for creating the IRQ domain, the
> gpio_irq_chip structure is now filled by the driver itself and then
> gpiochip_add_data() takes care of instantiating the IRQ domain for us.
>
> Suggested-by: Andy Shevchenko <andy.shevchenko-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> Signed-off-by: Dmitry Osipenko <digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
>


Looks good to me.
Acked-by: Laxman Dewangan <ldewangan-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>

Re: [PATCH v3 5/6] gpio: max77620: Use irqchip template

[Laxman Dewangan]

On Thursday 09 July 2020 01:53 AM, Dmitry Osipenko wrote:
> External email: Use caution opening links or attachments
>
>
> This change addresses one of the GPIO-core TODOs for the MAX77620 driver
> which requires modern drivers to use the irqchip template. Instead of
> using the GPIO's irqchip-helpers for creating the IRQ domain, the
> gpio_irq_chip structure is now filled by the driver itself and then
> gpiochip_add_data() takes care of instantiating the IRQ domain for us.
>
> Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
>


Looks good to me.
Acked-by: Laxman Dewangan <ldewangan@nvidia.com>

Re: [PATCH v3 6/6] gpio: max77620: Initialize hardware state of interrupts

[Laxman Dewangan]

On Thursday 09 July 2020 01:53 AM, Dmitry Osipenko wrote:
> External email: Use caution opening links or attachments
>
>
> I noticed on Nexus 7 that after rebooting from downstream kernel to
> upstream, the GPIO interrupt is triggering non-stop despite interrupts
> being disabled for all of GPIOs. This happens because Nexus 7 uses a
> soft-reboot, meaning that bootloader should take care of resetting
> hardware, but the bootloader doesn't do it well. As a result, GPIO
> interrupt may be left ON at a boot time. Let's mask all GPIO interrupts
> at the driver's initialization time in order to resolve the issue.
>
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
>


Looks good to me.
Acked-by: Laxman Dewangan <ldewangan@nvidia.com>

Re: [PATCH v3 6/6] gpio: max77620: Initialize hardware state of interrupts

[Laxman Dewangan]

On Thursday 09 July 2020 01:53 AM, Dmitry Osipenko wrote:
> External email: Use caution opening links or attachments
>
>
> I noticed on Nexus 7 that after rebooting from downstream kernel to
> upstream, the GPIO interrupt is triggering non-stop despite interrupts
> being disabled for all of GPIOs. This happens because Nexus 7 uses a
> soft-reboot, meaning that bootloader should take care of resetting
> hardware, but the bootloader doesn't do it well. As a result, GPIO
> interrupt may be left ON at a boot time. Let's mask all GPIO interrupts
> at the driver's initialization time in order to resolve the issue.
>
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
>


Looks good to me.
Acked-by: Laxman Dewangan <ldewangan@nvidia.com>

Re: [PATCH v3 2/6] gpio: max77620: Fix missing release of interrupt

[Dmitry Osipenko]

09.07.2020 17:57, Laxman Dewangan пишет:
> 
> 
> On Thursday 09 July 2020 01:53 AM, Dmitry Osipenko wrote:
>> External email: Use caution opening links or attachments
>>
>>
>> The requested interrupt is never released by the driver. Fix this by
>> using the resource-managed variant of request_threaded_irq().
>>
>> Fixes: ab3dd9cc24d4 ("gpio: max77620: Fix interrupt handling")
>> Signed-off-by: Dmitry Osipenko <digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> 
> 
> Looks good to me.
> Acked-by: Laxman Dewangan <ldewangan-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>

Hello, Laxman! Thank you very much for taking a look at this series!

I missed to add the stable tag to this patch, so will prepare a v4 with
the corrected tag. I'll also add yours acks and Andy's r-bs to the
patches. Thanks!

Re: [PATCH v3 2/6] gpio: max77620: Fix missing release of interrupt

[Dmitry Osipenko]

09.07.2020 17:57, Laxman Dewangan пишет:
> 
> 
> On Thursday 09 July 2020 01:53 AM, Dmitry Osipenko wrote:
>> External email: Use caution opening links or attachments
>>
>>
>> The requested interrupt is never released by the driver. Fix this by
>> using the resource-managed variant of request_threaded_irq().
>>
>> Fixes: ab3dd9cc24d4 ("gpio: max77620: Fix interrupt handling")
>> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> 
> 
> Looks good to me.
> Acked-by: Laxman Dewangan <ldewangan@nvidia.com>

Hello, Laxman! Thank you very much for taking a look at this series!

I missed to add the stable tag to this patch, so will prepare a v4 with
the corrected tag. I'll also add yours acks and Andy's r-bs to the
patches. Thanks!